The invention relates to a deflector for an aircraft, to the use of a deflector in an aircraft, and to a method for discharging fluids from an aircraft to the environment of the aircraft.
Hereinafter, the term “deflector” refers to devices and arrangements that are designed to discharge fluids from the interior of an aircraft to the environment. It is well known that fluids may be discharged by way of an outlet of an aircraft, wherein such an outlet is positioned so as to be flush with the exterior skin of the aircraft. Optionally, the outlet may be closed by means of a blind plug, wherein the blind plug may be pushed out as a result of the pressure of the discharging fluid. However, in the case of an outlet that is arranged so as to be flush with the exterior skin, any fluid to be discharged will contact the exterior skin of the aircraft in flight and thus render said skin wet. In the case of structure-damaging fluids, which cause particularly strong soiling, the danger of fire or the like, this manner of discharging fluid is not particularly advantageous.
To this effect in the state of the art so-called drainage masts are used, which are designed as rigid and permanently projecting pipes. The respective pipe is preferably aerodynamically enclosed in a fairing and is situated in the flow field of the aircraft so that the fluid to be released may not contact the exterior skin of the aircraft.
In addition, guiding plates according to FIGS. 1 and 2 exist, which are arranged rigidly obliquely in the flow field of the aircraft, through which guiding plates the discharging fluid is deflected away from the flow field so that a situation is avoided in which the fluid may contact the exterior structure of the aircraft.
Up to now, the discharge of structure-damaging gaseous fluids has been handled in various ways. Air conditioning outlets in aircraft discharge air with a relatively small increase in temperature so that this requires only minor arrangements in order to protect the structure. Oil cooler outlets of auxiliary power units (APUs) also only discharge air with a relatively small increase in temperature. In this case an exit opening comprising a relatively small titanium fairing is sufficient. Up to now, in aircraft, exhaust gases from auxiliary power units have been discharged at the rear of a tail cone, wherein this is a position in which the exhaust gas under any wind conditions and flight conditions no longer reaches the structure or the exterior skin of the aircraft at a concentration that would be sufficient to heat up the exterior skin of the aircraft.
However, exhaust outlets are also known that are arranged within the aerodynamic fairing of aircraft wings. In this region, as a result of wind and as a result of the aerodynamic conditions in flight operation, the so-called exhaust plume of the auxiliary power unit is pushed onto the structure or the exterior skin of the aircraft. However, there is the option of cooling the exhaust gas by means of extraneous air, as a result of which any deflector may be designed to be significantly smaller, or may even be done without entirely.
Due to the fact that various fluid sources may exist from which fluids need to be discharged, several deflectors may be necessary on an aircraft. However, various systems that drain the fluids may simply be coupled. In this way, liquids from various sources may be drained with the use of just one drainage mast. A fixed projecting drainage mast on an aircraft is more economical if said drainage mast is used for draining various sources.
Known systems for the discharge of gases may not, however, be used for other purposes or be coupled without further ado. Gas to be discharged would flood a pipe network used for coupling, which in the case of combustible gases could pose a risk. Furthermore, if an emergency system for discharging combustible gases is integrated in the aircraft, which emergency system is only seldom or never used, the resulting aerodynamic resistance is very significant. Without the use of a deflector that projects into the air flow, a combustible gas that is to be discharged would contact the exterior structure of the aircraft and would reach heated-up regions, for example engines or the like, thus compromising the safety of the aircraft.
The above-described deflectors from the state of the art are associated with a number of disadvantages, with the permanent projection of the deflector into the airflow surrounding the aircraft being particularly serious. As a result of it the aerodynamic resistance of the aircraft is permanently increased, which is unacceptable in view of aircraft design criteria to the contrary. Furthermore, none of the deflectors shown in the state of the art is specially designed for the discharge of combustible gases in emergencies, so that it would result in the smallest possible increase in aerodynamic resistance.